The present invention relates to making composite material parts, and more particularly to making fiber reinforcing structures for such parts.
The field of application of the invention is more particularly that of making parts out of structural composite material, i.e. parts having a fiber reinforcing structure that is densified with a matrix. Composite materials make it possible to make parts of overall weight that is lighter than the weight which the same parts would have if they were made of metal.
Parts of standard shapes made out of composite material generally present good structural characteristics and high strength, in particular because the fiber reinforcement of the part is usually made as a single piece and thus enables the mechanical forces acting on any portion of the part to be well distributed.
In contrast, when making composite material parts that are more complex in shape, and in particular parts having one or more elements for supporting the part as a whole, it is generally not possible to have high mechanical strength over the entire part.
By way of example, when using a composite material to make an aeroengine casing that has one or more suspension yokes for attaching the engine to the wing of an airplane, the fiber reinforcement in the suspension yoke(s) is fabricated independently of the fiber reinforcement of the casing shroud and is subsequently added thereto, e.g. by stitching or by adhesive. Because of the very great mechanical stresses (several thousands of tons) that act on engine-support yokes, such a casing design cannot provide sufficient mechanical strength. Consequently, that type of part is presently always made out of metal and consequently presents relatively high overall weight.